C. Septier

Determination of taste-active compounds of a bitter Camembert cheese by omission tests

The taste-active compounds of a Camembert cheese selected for its intense bitterness defect were investigated. The water-soluble fraction (WSE) was extracted with pure water and fractionated by successive tangential ultrafiltrations and nanofiltration. The physicochemical assessment of these fractions led to the construction of a model WSE which was compared by sensory evaluation to the crude water-soluble extract, using a panel of 16 trained tasters. As no significant difference was perceived, this model WSE was then used directly or mixed with other cheese components for omission tests. Among the main taste characteristics of the WSE (salty, sour, umami and bitter), bitterness was found to be due to small peptides whose mass distribution was obtained by RPHPLC-MS (400-3000 Da) and whose taste properties are discussed.

IDENTIFICATION AND SENSORY EVALUATION OF THE CHARACTER-IMPACT COMPOUNDS OF GOAT CHEESE FLAVOUR

1 SUMMARY The volatile compounds of various goat cheeses have been isolated in order to identify the character-impact odorants by a combination of instrumental analyses and sensory studies. Different extraction procedures have been studied in order to obtain a volatile fraction representative of the cheeses. The most representative extract, as determined by sensory evaluation, has been submitted to GC-MS and to GC-olfactometry, using the aroma extract dilution analysis (AEDA) method. The volatile fatty acids have been found to be the most important compounds for the characteristic goat flavour. Among them, branched-chain fatty acids ( e.g. , 4-methyloctanoic and 4-ethyloctanoic) have been found to be particularly important. Finally, incorporation of volatile extracts and individual synthetic components into a cheese model allowed the flavour impact-compounds identified to be evaluated sensorially.

Isolation of a peptidic fraction from the goat cheese water-soluble extract by nanofiltration for sensory evaluation studies

Abstract The effect of the small water-soluble peptides on the taste of cheeses has not been clarified yet because of the high difficulties to isolate them from the other water-soluble compounds. A new filtration method, nanofiltration, using ionizable membranes, allowed us to purify a peptidic fraction prepared from the permeate obtained by ultrafiltration (MWCO=1000) of a goat cheese water-soluble extract. A large proportion of mineral salts and a part of amino acids were eliminated from the nanofiltration retentate where a majority of small peptides were concentrated. The peptidic fraction was incorporated in a cheese model with known synergistic effectors such as mineral salts and amino acids. Sensory evaluation was done bysome omission tests. The results showed that the small peptides fraction had no effect on the taste of the cheese and no synergistic effects were observed. The nanofiltration technique showed its interest and should be applied to other cheeses and foodstuffs after optimization.

Identification of tasty compounds of cooked cured ham: Physico-chemical and sensory approaches

Abstract Tasty compounds from meat have not been studied in depth. The aim of this work was to isolate, identify and quantify tasty compounds from cooked cured ham and to link them to the sensory evaluations of the fractions from which they are extracted. The extraction of the water-soluble fraction from ham was done by an hydraulic press. The crude extract was ultrafiltered and both gel filtration and nanofiltration allowed to obtain edible fractions. Some links between the physicochemical and sensory data have been found, in particular, the umami taste was related to the presence of IMP and monosodium glutamate. The direct influence of proteolytic peptides on this taste is discussed. Moreover, the nanofiltration appears useful to remove salts from the extract but this technique needs to be optimized for a particular study of ham peptides.